Don't all these free proxy services always fall prey to blacklists because scammers,etc abuse them until they're useless?

Wow, exfiltrating data has never been easier!

Probably why they used the trycloudflare.com domain as they expect it to be blocked.

Can confirm. Coming from ngrok, the main reason we had to make tunneling not anonymized etc was because of scammers, etc on the internet. Other players in the space bypass this by open sourcing the tech, or separating the architecture entirely. This is cool and all, but ultimately gives nefarious actors on the internet more opportunities.

Yes they actually do, but because its cloudflare which is offering this, blacklisting it might lead to blacklisting can be more negative and cloudflare has a much higher incentive to not make these tunnels useless. They are also more powerful and can fix things which would be harder for smaller companies to handle (atleast within the context of cloudflare tunnels)